BACKGROUND TO THE INVENTION . . .
SUMMARY OF THE INVENTION . . .
BRIEF DESCRIPTION OF THE DRAWINGS . . .
DETAILED DESCRIPTION OF THE INVENTION . . .
DEFINITIONS . . .
STRUCTURAL UNITS . . .
DESIGN AND PRODUCTION OF THE ROD PROTEINS . . .
ASSEMBLY OF INDIVIDUAL ROD COMPONENTS INTO NANOSTRUCTURES . . .
STRUCTURAL COMPONENTS FOR SELF ASSEMBLY OF BEAMS IN VITRO . . .
APPLICATIONS . . .
KITS . . .
EXAMPLE 1: DESIGN, CONSTRUCTION AND EXPRESSION OF INTERNALLY DELETED P37 . . .
EXAMPLE 2: DESIGN, CONSTRUCTION AND EXPRESSION OF A gp37-36 CHIMER . . .
EXAMPLE 3: MUTATION OF THE GP37-36 CHIMER TO PRODUCE COMPLEMENTARY SUPPRESSORS . . .
EXAMPLE 4: DESIGN, CONSTRUCTION AND EXPRESSION OF A gp36-34 CHIMER . . .
EXAMPLE 5: ISOLATION OF THERMOLABILE PROTEINS FOR SELF-ASSEMBLY . . .
EXAMPLE 6: ASSEMBLY OF ONE-DIMENSIONAL RODS . . .
EXAMPLE 7: STAGED ASSEMBLY OF POLYGONS . . .
The present invention pertains to nanostructures, i.e., nanometer sized structures useful in the construction of microscopic and macroscopic structures. In particular, the present invention pertains to nanostructures based on bacteriophage T4 tail fiber proteins and variants thereof.
While the strength of most metallic and ceramic based materials derives from the theoretical bonding strengths between their component molecules and crystallite surfaces, it is significantly limited by flaws in their crystal or glass-like structures. These flaws are usually inherent in the raw materials themselves or developed during fabrication and are often expanded due to exposure to environmental stresses.
The emerging field of nanotechnology has made the limitations of traditional materials more critical. The ability to design and produce very small structures (i.e., of nanometer dimensions) that can serve complex functions depends upon the use of appropriate materials that can be manipulated in predictable and reproducible ways, and that have the properties required for each novel application.
Biological systems serve as a paradigm for sophisticated nanostructures. Living cells fabricate proteins and combine them into structures that are perfectly formed and can resist damage in their normal environment. In some cases, intricate structures are created by a process of self-assembly, the instructions for which are built into, the component polypeptides. Finally, proteins are subject to proofreading processes that insure a high degree of quality control.
Therefore, there is a need in the art for methods and compositions that exploit these unique features of proteins to form constituents of synthetic nanostructures. The need is to design materials whose properties can be tailored to suit the particular requirements of nanometer-scale technology. Moreover, since the subunits of most macrostructural materials, ceramics, metals, fibers, etc., are based on the bonding of nanostructural subunits, the fabrication of appropriate subunits without flaws and of exact dimensions and uniformity should improve the strength and consistency of the macrostructures because the surfaces are more regular and can interact more closely over an extended area than larger, more heterogeneous material.
In one aspect, the present invention provides isolated protein building blocks for nanostructures, comprising modified tail fiber proteins of bacteriophage T4. The gp34, 36, and 37 proteins are modified in various ways to form novel rod structures with different properties. Specific internal peptide sequences may be deleted without affecting their ability to form diners and associate with their natural tail fiber partners. Alternatively, they may be modified so that they: interact only with other modified, and not native, tail fiber partners; exhibit thermolabile interactions with their partners; or contain additional functional groups that enable them to interact with heterologous binding moieties.
The present invention also encompasses fusion proteins that contain sequences from two or more different tail fiber proteins. The gp35 protein, which forms an angle joint, is modified so as to form average angles different from the natural average angle of 137xc2x0 (xc2x17xc2x0) or 156xc2x0 (xc2x112xc2x0), and to exhibit thermolabile interactions with its partners.
In another aspect, the present invention provides nanostructures comprising native and modified tail fiber proteins of bacteriophage T4. The nanostructures may be one-dimensional rods, two-dimensional polygons or open or closed sheets, or three-dimensional open cages or closed solids.